Conventionally, density of data that is stored in a magnetic disk in a hard disk device tends to be increased. With the increase of data density, a track pitch of the magnetic disk tends to be further made narrower, in recent years.
Upon writing data into such the magnetic disk with a head, if the head is positioned off the target track of the magnetic disk in a direction of an adjacent track in which data is written, it may influence a sector of the adjacent track. As an example of the influence, read performance on the sector is deteriorated; thereby there is a possibility that data cannot be read from the sector in some cases.
Therefore, there is proposed a technique for preventing data written into the adjacent track from being unreadable.
However, in conventional techniques, the same data is rewritten into the adjacent track in which read performance thereof has been deteriorated due to the misalignment of the head with respect to the target track. This requires the head to move to the adjacent track, and so on; thereby resulting in delay.